Greenhouse Gases, Global Warming, and Climate Change: Part Two
“When you’ve spent half your political life dealing with humdrum issues like the environment, it’s exciting to have a real crisis on your hands.” —Margaret Baroness Thatcher, former UK Prime Minister, on the Falkland Islands War
This is Venus, our planet’s next-door neighbor in the direction of the Sun. Of all the planets in our solar system, Venus is the one most similar to Earth in size and composition. The principal difference between Venus and Earth, at least in terms of composition, is that the atmosphere of Venus is very thick, very dense, and composed almost entirely of greenhouse gases, mainly carbon dioxide. Most of the rest is nitrogen, which is the primary ingredient in our own atmosphere.
Although Mercury is much closer to the Sun than Venus, Venus’ ultra-thick carbon dioxide atmosphere keeps its surface much hotter than that of Mercury, on average. Atmospheric pressure at the surface of Venus is about 90 times that of Earth, and the carbon dioxide clouds keep the mean surface temperature of Venus at a relatively uniform and quite balmy 800 degrees Fahrenheit (roughly 400 degrees Celsius.)
It goes without saying that no life can exist on Venus. But Venus wasn’t always this hellish.
Several billion years ago, the atmospheres of Earth and of Venus were remarkably similar. Liquid water is thought to have once been abundant on Venus’ surface. But because Venus is closer to the Sun than Earth, more geologically active than Earth, and therefore intrinsically hotter than Earth, the unchecked evaporation of this surface liquid generated huge amounts of carbon dioxide. At some point the CO2 levels in Venus’ atmosphere reached a critical level and a runaway greenhouse effect was triggered. Venus’ oceans never stabilized as our seas did. This greenhouse effect eventually replaced the Sun as Venus’ immediate heating mechanism, and caused the surface temperature of the planet to surpass that of Mercury. The greenhouse effect on Venus is now so strong that Venus literally no longer requires the heat of the Sun to stay boiling hot for long periods of time. Its sulfuric acid cloudtops reflect the vast majority of the shortwave energy it receives from the Sun; the CO2 atmosphere traps what radiation engages it. Venus is a reminder, floating brightly alongside us, of the dangers of a runaway greenhouse effect and of the fragility of the precious balance in which Earth’s congenial climate is maintained.
We discussed in Part One of this piece the means through which microbial and plant life interact with Earth’s atmosphere to keep its composition and temperature stable. It was largely the evolution of primordial life which kept Earth, through its very respiration, from becoming a greenhouse nightmare itself. How ironic, then, that it is the industrial activity of the most highly evolved form of life on Earth which is now the principal threat to the biological balance so carefully crafted by unicellular organisms beginning billions of years ago. It is a heartbreaking dilemma. But we don’t have time for heartbreak if we are to do something about it.
Are humans responsible for global warming?
I’m not trying to be a smartass, but that quite literally depends on what one means by “responsible” and “global warming.” Allow me to explain.
As the millions of years continue to creep by, the Sun is getting hotter. In our day the Sun radiates about 30% more energy than it did in the period in which life first appeared on Earth. Eventually the Sun will become so hot that the surface temperatures of Earth will match those of the Venus of today, and increased levels of harmful shortwave radiation at our planet’s surface will exacerbate the blaze. That’s a billion years down the road. So, global warming, then, is something that happens naturally as a byproduct of stellar evolution. That the Earth is eventually going to fry is not something which is disputed. In a perfect world, humanity will develop means to explore and colonize space and it is not entirely inconceivable that the technologies of many thousands of years in the future might even provide a way to alter stellar evolution, to prolong the life of our star and of our planet. So natural global warming is not something which is perceived widely to be an immediate threat to life on Earth, and it is certainly not something for which humankind is responsible.
The primary lesson we can learn from the history of Venus is that this ‘natural’ global warming provided by the Sun is not the only means through which the Earth can be baked until crisp. The reason Venus is about twelve times hotter than Earth has little to do with its closeness to the Sun, and everything to do with the fact that greenhouse gases, through natural processes, ran rampant in its atmosphere long ago. Venus is closer to the Sun than Earth—but, again, it reflects a great deal of the radiation it receives from the Sun, certainly moreso than Earth. It is the greenhouse effect which keeps the surface of the planet hot enough to melt lead.
This is why I disfavor the term “global warming” to describe the increasing levels of greenhouse gases and the rising temperatures which are resulting from human industrial activity. Through its ambiguity, it plays into the hands of those whose salaries and lifestyles hinge on continued ignorance of the crisis at hand. Human beings are not responsible for global warming, in the most concrete sense. But we are responsible for contributing to an atmospheric imbalance which is going to rapidly accelerate the rate of global warming through the greenhouse effect if this balance is not restored and maintained.
Don’t greenhouse gases come from plants and from volcanos? Are we really contributing very much to greenhouse gas levels, at least compared to these natural sources?
We discussed in Part One that, in earlier times on Earth, volcanos and geologic activity were the primary sources of CO2 and other greenhouse gases in our atmosphere. At one point, a strong greenhouse effect was desirable because the initial thickness and radiative reflectivity of the Earth’s atmosphere (more than 100 times its present thickness) would have caused the Earth to freeze solid had it not been for the heat-trapping effects of greenhouse gases. Hundreds of millions of years ago, greenhouse gas concentrations in Earth’s atmosphere were much, much higher than today. That, of course, was prior to the development of complex life, which requires much less CO2 and much more free oxygen to survive.
The Earth is not as volcanically active today as it was back then. Today, volcanic emissions release about 200 million tons of greenhouse gases into the atmosphere each year. Human industrial activities, in contrast, released about 6,500 million tons of CO2 into the atmosphere in the year 2000.
Hmmm. 6,500,000,000 tons of manmade CO2 versus 200,000,000 tons of volcanic CO2. I’d say that’s quite a contribution we’re making to greenhouse gas levels. Yes, I’d say we’re doing our part and then some.
Plant respiration consumes considerable amounts of CO2, converting it into O2 through photosynthesis. This is why massive deforestation contributes to escalating CO2 levels. The point is that ‘natural’ emissions of CO2 are countered by bioprocesses carried out within a carefully balanced cycle that has developed over the course of about three billion years. Oceanic algae alone can do much to keep carbon dioxide levels within reason by converting the CO2 in the water into the O2 that animal life needs to breathe. Earth’s ecology is equipped to deal with 200 million tons of annual volcanic CO2. It is not equipped to deal with 6.5 billion tons of annual human contributions, particularly not when these contributions have all been made inside of the roughly 200-year period since the beginnings of our Industrial Revolution.
Oops. Our bad, Earth.
The graph at right, produced by an independent, peer-reviewed study in 2003 with no ties to the fossil fuel industry, shows those CO2 emissions for which mankind is responsible through fossil fuel burning. This does not account for the CO2 emissions caused by deforestation, which are also quite significant. Keep in mind that the level of atmospheric CO2 produced by volcanos in a given year in the modern period would register at approximately the same level given for cement production alone, per this data. This is a more stark and graphic depiction of the maniacally severe impact of manmade CO2 emissions on atmospheric composition.
The President of the United States and his good buddies such as Michael Crichton, everyone’s favorite science-gone-mad fictionalist, continue to maintain that we just can’t be too sure about the impact of human emissions on atmospheric composition. They say that the 6.5 billion tons of CO2 human industry released into the atmosphere in one year alone is good for plants, because plants need CO2. Well, I need food to eat. But if you feed me thirty times as much food as I am used to eating, is that good for me? Or would it kill me?
I, for one, beg to f*&(#ng differ, and I’m not alone. There are people much more knowledgable than I who are alarmed at these cynical opinions from centers of power. A recent survey of 900 peer-reviewed scientific publications in climate studies revealed not one relevant publication which took issue with either the factual validity or the grave and immediate implications of the data you’re looking at. The tiny, chihuahua-like minority of scientists which remains unimpressed with these figures can, almost universally, be linked to funding or other professional associations with governments and fossil fuel industries, as we will discuss at length in Part Three. The threat of political terrorism hardly compares with the threat of extinction.
There is no serious debate about the impact of human industrial activities on climate change. The only arguments come in the form of cynical dismissals from oil companies, congressmen, the popular press, and folks like the veritable sages at junkscience.com. Take a look at junkscience.com—it’s run by Steven Milloy, a FOX News columnist whose various mutual funds and science-for-profit schemes have been moneyed by Phillip Morris and ExxonMobil, the folks who brought you lung cancer and oil spills. Milloy has more college degrees than you and I have fingers on one hand. His deceitfully crafted and totally deranged explanation for why “CO2 doesn’t trap heat” I find particularly hilarious and forgettable. You’ll see right away he doesn’t miss a beat in promoting his books and DDT T-shirts. The link will open in a new window so you can close it before you puke. I meant to save discussion of his shameful and profitable lies for Part Three, but, frankly, it’s hard to resist. His entire argument for explaining away the greenhouse effect hinges on his assertion that CO2 doesn’t really “trap” heat, it just “delays its radiation back into space.” Among many other purposeful emissions—I mean, omissions—what he doesn’t tell you is that this “delay” can be MILLIONS OF YEARS LONG depending on variables ranging from ocean convection to solar surface fluctuations. <rhetoric>Do you see the radar image of Venus’ surface at the bottom of the page, Mr. Milloy? Do you see that 800 degree greenhouse gas hell?</rhetoric> Well, don’t pity Venus—it’s all just part of an inconvenient three billion years-long delay we’ll call the Milloy Cycle. His graphs, though almost totally devoid of any meaning, are impressive to the illiterate, I suppose. I apologize for wasting so much of your time on this quack, and I’ll sum up with an analogy: Steven Milloy : climatology as Ann Coulter : foreign policy. You be the judge. You don’t have to take my word for it—ask any credible scientist in the world whose principal income isn’t derived from whoring around the Fortune 500.
2006 will be the hottest year on record throughout the past 100,000 years, just as 2005 was before it. Hurricane seasons will become longer and more severe, and melting ice sheets will continue to dump huge amounts of freshwater into the oceans, fundamentally disturbing intercontinental currents and weather patterns. Droughts will dominate what were once wetlands. Temperatures higher than any yet experienced by mankind are on their way, and it may already be too late to prevent them. This is because escalating CO2 levels produce escalating temperatures after a period of latency perhaps a hundred years long, on average. The heat we are experiencing now is not a product of the industrial activities of the last few decades. It is the product of the first rising slope you see in the line above, between 1850 and 1900. The temperatures that will result from increased CO2 emissions from 1950 to the present have not yet been felt. We’re saving those for the great-grandkids.
This doesn’t mean it’s time to give up hope. Far from it—everywhere one looks, one can see inspiring examples of real people who are doing their parts to lead sustainable lifestyles in spite of the many challenges. They publish some of the best blogs on the Web. This is key. Public awareness and outcry are also key. It may be too late to correct some of the damage, but if we do not act quickly and decisively to drastically reduce our impact on the atmosphere and the biosphere, the end of life, or at least of complex life, on Earth may be only a few hundred years away, a few thousand at most. That’s a harsh reality to face, especially for manufacturers and fossil fuel companies. But companies don’t have children. People do. If you’ll forgive me a bit of poetic license, Venus is probably screaming right about now. “You don’t have to end up like this, not for a billion years yet!” she cries into the vacuum of space. “Don’t you care? Are you really intelligent life? Look at me!”
A radar-imaged depiction of the surface of Venus.
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